Device and holder therefor for inserting a hollow coupling member into bone marrow

ABSTRACT

The invention relates to a device for inserting a hollow coupling member into the bone marrow of man or animals. Fluid may be supplied to the bone marrow through the inserted coupling member. The device according to the invention comprises an assembly of a striker-pin holder, a striker pin and a coupling member which is movably accommodated in an elongate housing and on which a force can be exerted by a source of energy provided in the device. When this force is exerted the striker pin and the coupling member are driven into the bone marrow, whereupon the coupling member can be detached from the remainder of the device.

United States Patent [191 11] 3,815,605 Schmidt et al. June 11, 1974 [54] DEVICE AND HOLDER THEREFOR FOR 3,128,768 4/1964 Geistauts 128/305 INSERTING A HOLLOW COUPLING 3,225,760 12/1965 Di Cosola... "128/83, MEMBER INTO BONE MARROW 3,528,425 9/1970 Banko 128/305 [75] lnventors: Ernst Machiel Schmidt; Hendrik n post both of Emmasingel, Primary Exammer--Lucie l-l. Laudenslager Eindhoven, Netherlands Attorney, Agent, or Firm-Frank R. Trifari [73] Assignee: U.S. Philips Corporation, New

[57 ABSTRACT 22 F] d: M 11 1972 1 l e 8y The invention relates to a device for inserting a hollow PP 252,375 coupling member into the bone marrow of man or animals. Fluid may be supplied to the bone marrow [30] Foreign Application Priority Data through the inserted coupling member. The device ac- M 19 1971 N h l d cording to the invention comprises an assembly of a 3 1972 7106896 striker-pin holder, a striker pin and a coupling memar. et er an S e is movably accommodated i an g e housing and on which a force can be exerted by a 13/158328; Source of energy provided in the device when this [58] d 83 2 B force is exerted the striker pin and the coupling memm her are driven into the bone marrow, whereupon the ling member can be detached from the remainder [56] References Cited ith d UNITED STATES PATENTS o e evlce 2,818,852 l/l958 Kugler 128/305 X 13 Claims, 12 Drawing Figures l6- -18 13- /10 s I -1 H a I: 2 i' 17 '1 I 1 i I -11 a t l i T 79 5 7-19 1N5 2o 25 *fi' A ge -26 2 t- 7w mm 3815605 SHEET 2W8 Fig.6.

PATENTEDJUN 1 1 I974 PATENTEDJUN 11 m4 SHEEI t 0F 8 PATENTEUJUN 1 m4 38151605 sum 5 or s varr:

PATENTEnJun 1 1 I914 PATENTEDJUR 1 1 I974 SHEET 7 OF 8 Fig."

DEVICYEAND HOLDER THEREFOR FOR INSERTING A HOLLOW COUPLING MEMBER INTO BONE MARROW This invention relates to a device for inserting a substantially hollow coupling member into the bone marrow of man or animals. The member has a pointed part provided with a central bore and at the end remote from the pointed part can be connected to a conduit for a liquid, or fluid.

In a known device the coupling member to be inserted is provided with an external self-tapping screwthread. The coupling member is screwed into the bone marrow by means of a hande which is removably attached to it. Screwing may be effected manually or by means of a motor.

This device has the disadvantage that the insertion of the coupling member takes much time and may in general be performed only by a surgeon or another highly qualified medical person. A further disadvantage is that drilling swarf is likely to be produced and may clog the coupling member, in particular its lateral discharge opening. The known device further has the drawback that the sterility of the instrument when inserted into the bone is not absolutely guaranteed. It should also be noted that owing to the differences in thickness of the skin and the subcutaneous connective tissue which occur in man and animals the depth of penetration of the coupling member into the bone may vary, with a consequent risk of excessive penetration.

We have now developed a device of the aforementioned type which does not have the said disadvantages. The device according to the invention is characterised by an assembly of a striker pin holder, a striker pin made of a hard material and connected to the holder, and a coupling member. The assembly is movable in an elongate housing, the striker pin extending through a central bore of the coupling member beyond the end thereof. The housing at the striker-pin end is either open or is provided with a diaphragm through which at least, part of the striker-pin can pass. A mechanism for actuating a source of potential energy is provided to exert a force on the striker-pin holder.

Operation of the actuating mechanism causes a source of potential energy, such as a compressed spring, to be rapidly released so as to exert a force on the assembly comprising the striker-pin holder, the striker pin and the coupling member. As a result, the assembly moves in the housing in the direction of length thereof. Parts of the striker pin and of the coupling member move beyond the open end of the housing, during which movement they may pierce a diaphragm, through a distance such that when the device according to the invention is actuated, the open end of the housing is pressed against the skin of a patient at right angles thereto. The striker pin and the coupling member penetrate through the skin and the outer compact bone layer or lamina externa into the bone marrow or diploe. 1

After the striker pin and the coupling member have been inserted or, properly speaking, driven in, the housing, the striker-pin holder and the striker pin are disconnected from the coupling member. To the free end of the inserted coupling member a conduit for a fluid maybe connected and a fluid, for example an infusion fluid, may be introduced into the bone marrow through this. conduit and the central bore in the coupling member.

Alternatively a sternal puncture may be performed.

In comparison with the known device the present invention has the advantage that the insertion speed of the coupling member is very high. This provides considerable saving in time, which particularly in the case of large-scale disasters when many patients have to be treated is of vital importance. Further advantages of the device according to the invention are the simplicity of operation, maintenance of sterility during the insertion of the coupling member and reliability. With regard to the reliability it should be noted that the discharge opening in the form of the end of the central bore of the coupling member inserted into the bone marrow always remains free. When the coupling member is inserted into the bone marrow the discharge opening is securely screened by the projecting tip of the striker pin, so that the discharge opening is not likely to be clogged. Removal of the striker pin from the coupling member provides a free passage for the fluid to be introduced or withdrawn.

The aforementioned displacement of the assembly comprising the striker-pin holder, the striker pin and the coupling member must be such that the coupling member and the striker pin do not pierce the lamina interna lying beneath the diploe. To avoid excessive depth of penetration of the coupling member and the striker-pin tip into the bone, the elongate housing is provided with a shoulder which forms a stop for the striker-pin holder. Such a stop may, for example, consist of a thickened wall part near the open end of the housing. In a preferred embodiment slots are made in the inner wall of the elongate housing. The slots extend to within some distance from the open end of the housing and their end walls form stops for projections of the striker-pin holder which fit in the slots. When the device according to the invention is actuated the strikerpin holder moves in the housing until it or the said projections abut against thestop or stops. Thus the length of stroke of the striker-pin holder and hence of the striker pin and the coupling member connected to it is restricted.

The depth of penetration of the coupling member and the striker-pin tip into the bone marrow is influenced by the thickness of the skin tissue and adipose tissue overlying the lamina externa. To eliminate this influence, an auxiliary member may be provided which enables the penetration depth of the coupling member and the striker-pin tip into the bone marrow to be exactly determined. The auxiliary member is connected to the coupling member or to the elongate housing and comprises at least one cutting edge, blade or pointed projection. Each cutting edge, blade or pointed projection is suitable to cut through or pierce skin tissue and adipose tissue'but cannot penetrate into the lamina externa. When the device is actuated the auxiliary member cuts through the skin but is arrested by the lamina externa. The coupling member and the striker-pin tip can project at most 6 or 7 mm beyond the auxiliary member, so that when the cutting edge of the auxiliary member abuts the lamina externa the coupling member and the striker-pin tip can extend into the bone marrow for at most 6 or 7 mm.

The auxiliary member may take different forms. For example, one embodiment provides that the auxiliary member comprises pins provided on the thickened wall part of the elongate housing which forms a stop for the striker-pin holder. The pins may alternatively be provided on a cover which is detachably connected to the elongate housing. The cover closes the open end of the housing.

In another interesting embodiment the auxiliary member comprises a stylet or perforator which is joined to the coupling member at a distance of about 6 or 7 mm from the end of this member and is provided with at least one winglike projection having a cutting edge. The stylet is preferably secured to the coupling member so as to be capable of rotating about it. In a highly advantageous embodiment the auxiliary member comprises a table-like body having a plurality of legs, preferably three or four. The legs are provided with cutting edges at their free ends. The part of the tablelike body remote from the legs is provided with a hole for the passage of the coupling member. The table may be connected to the coupling member, for example by means of a retaining ring.

In a preferred embodiment of the device according to the invention the table is detachably connected to the lower surface of the elongate housing. For this purpose the table is provided with a coupling part, such as a threaded part, which co-operates with a coupling part mounted onthe housing, for example a wire spring.

In the operation of this preferred embodiment of the device according to the invention first the legs of the table connected to the housing are thrust through the skinof a patient against the compact bone layer (1amina externa) and then by actuating the source of potential energy the coupling member and the striker pin are driven into the bone marrow through the hole in the table, piercing the skin and the lamina externa. The fact that the source of potential energy does not exert any force on the table provides the importantadvantage of entirely precluding the table from penetrating too far, i.e. not only through the skin but also through the lamina externa.

After the coupling member and the striker pin have been driven in, the housing is disconnected from the table by rotating it and then is removed together with the striker-pin holder and the striker pin. The table and the coupling memberremain in the skin and the bone respectively of thepatient.

The assembly of the striker-pin holder, the striker pin and the couplingmernber also may be realised in various embodiments. In any embodiment it is essential for the striker pin to extend in the central bore of the coupling member, the striker-pin tip projecting just beyond the end of the coupling member. This construction ensures that the central bore is closed by the projecting striker-pin tip so that the pointed part of the coupling member together with the striker-pin tip forms an insertion member. In the accompanying drawings various embodiments .of the assembly are shown. In an advantageous embodiment the striker-pin holder is a substantially cylindrical body in the lower part of which the striker pin is centrally secured. The lower part of the striker-pin. holder is further provided with a coupling part which co-operates-with a coupling part disposed on the upper surface of the coupling member. Thus the striker-pin holder and the coupling member are detachably connected. It should be noted that the coupling part of the coupling member preferably also is suitable for co-operation with a coupling part of the fluid conduit. In a preferred embodiment of the device according to the invention the part of the coupling member remote from the coupling part is provided with a tapered sawtooth screwthread. The sawtooth screwthread ensures that the coupling member is formly clamped in the bone, preventing liquid leakage between the bone and the inserted coupling member. In a highly interesting embodiment the device according to the invention includes a table-like auxiliary member which is detachably connected to the housing and is provided with a screwthreaded part, and a coupling member provided with a sawtooth screwthread, the thread direction of the screwthreaded part being opposite to that of the sawtooth screwthread.

In the practical use of this embodiment, after the legs of the auxiliary member have been thrust through the skin against the lamina externa and then the pointed part of the coupling member and the striker pin have been driven into the bone marrow through the hole in the auxiliary member, piercing the skin and the lamina externa, the housing is disconnected from the auxiliary member by turning. As will be seen from the following description of the drawings, this operation includes rotation of the coupling member. Since the thread direction of the sawtooth screwthread is opposite to that of the screwthreaded part of the auxiliary member, disconnection of the housing causes the coupling member to be screwed slightly deeper into the bone marrow. At the same time the upper part of the coupling member is firmly clamped in the hole formed in the auxiliary member. This ensures that the coupling member and the auxiliary member, which remain in the bone and the skin respectively of a patient, form a robust and securely clamped unit, which moreover has a very good transverse stability owing to the legs of the auxiliary member being inserted in the skin.

The part of the coupling member which in the use of the device penetrates into the bone marrow must be made of a vary hard material, such as, for example, steel. The upper part of the coupling member may be made of a softer material, such as a synthetic material. In an embodiment which is particularly advantageous from the point of view of manufacture the pointed steel part is firmly clamped in a plastics upper part.

Tests have shown that the human skin has a high tenacity and extensibility. It has been found that when a striker pin is used the free end of which is provided with a cutting edge the skin is far more readily-pierced, or properly speaking out through, than when astriker pin having a conical tip is used. To promote the sterility of the striker pin and the coupling member the striker pin holder and/or the elongate housing may be provided with at least one groove which provides a tight seal between the housing and the striker-pin holder.

The striker-pin holder and the striker pin and the coupling member connected to it are held in place by frictional forces acting between the striker-pin holder and the housing. Obviously, the frictional forces must be smaller than the force which the source of potential energy, such as a tensioned spring, is capable of exerting on the assembly of the striker-pin holder, the striker pin and the coupling member.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:

FIGS. 1, 2 and 3 refer to one embodiment of the device according to the invention,

FIGS. 4, 5 and 6 also relate to one embodiment which, however, is different from that shown in FIGS. 1, 2 and 3,

FIGS. 7 and 8 relate to a preferred embodiment of the device according to the invention, and

FIGS. 9 to 12 relate to various embodiments of the assembly of striker-pin holder, striker-pin and coupling member, which latter member may be provided with an auxiliary member.

FIG. 1 shows schematically a device according to the invention in which within a housing an assembly of a striker-pin holder, a striker pin and a coupling member engages a collar on which the force of a compressed spring is exerted. The housing is closed at one end by a detachable cover.

FIG. 2 shows the device of FIG. 1 with the spring expanded and a projecting part of the coupling member and the striker-pin tip inserted in the bone marrow.

FIG. 3 shows the coupling member remaining in the bone marrow after the housing containing the strikerpin holder and the striker pin has been removed. This Figure also shows the manner in which by means of an intermediate piece a fluid conduit is connected to the free end of the coupling member.

FIG. 4 shows part of a device according to the invention in which the lower end of the housing is closed by a cover which .is provided with pins and is detachably secured to the housing. The upper part of the device, which is notshown, is identical to that shown in FIG.

FIG. 5 shows a part of the same device to which FIG. 4 relates, with the spring expanded, so that a projecting part'of a coupling member together with a striker-pin tip has piercedthe cover provided with pins and has penetrated into the bone marrow. The remainder, not

shown, of the device of FIG. 5 corresponds to that shown in FIG. 2.

FIG. 6 shows the coupling member which is left in the bone marrow and the cover provided with pins which is left in the skin after the housing with the striker-pin holder and the striker pin has been removed.

FIG. 7 relates to a preferred embodiment of the device according'to the invention in which a tablelike auxiliary member is used which is detachably connected to the housing.

FIG. 8 shows the part of the device shown in FIG. 7 which in the operation of this device is left in the skin tissue and a bone of a patient.

FIG. 9 shows an assembly of a striker-pin holder, a striker pin and a coupling member in which the coupling member is provided with an auxiliary member in the form of a rotatable stylet.

FIG. 10 relates to an assembly of a striker-pin holder, a striker pin and a coupling member, in which the coupling member is provided with blades capable of penetrating into the bone marrow and with an abutting surface.

FIG. 11 shows an assembly of a striker-pin holder, a striker pin and a coupling member, in which the coupling member is provided with an abutting edge.

FIG. 12 shows an assembly of a striker-pin holder, a

striker pin, a coupling member and a tablelike auxiliary member connected to the coupling member.

Referring now to FIG. 1, a housing 1 is provided at one end withv a shoulder or stop 2 set with pins 3 and at the other end with an opening 4 in which fits a collar 5 of a spring sheath-6. The housing is further provided with a detachable cover 7. The spring sheath 6 contains a tensioned spring 8 which is enclosed between a collar 9 and a seat 10. The collar 9 is locked against displacement by a locking element 11 which is connected to the collar and its upper end has lugs 12. The lugs have externally tapered parts'l3 flat faces 14 of which bear against a rim of the seat 10. The housing 1 and the spring sheath 6 are surrounded by a displaceable sleeve 15 which has a conical bore 16 adapted to co-operate with the tapered parts 13 of the lugs 12. To prevent accidental actuation of the device a pin 17 extends in the space between the lugs 12 so that the latter cannot be pressed together. The pin 17 is provided with a cap 18 enabling it to be removed. The housing 1 contains a displaceable striker-pin holder 19 which is made of a resil ient material and is fonned with a recess adapted to receive a head 20 of a striker pin 21 made of a hard material, such as stainless steel. Into a second recess in the striker-pin holder 19 a coupling member 22 is inserted which is also made of a hard material and has a pointed part 23. The striker pin 21 extends in a central bore of the part 23 so that the tip 24 of the pin 21 protrudes slightly beyond the end of the central bore The strikerpin holder 19 further is provided with ribs 25 which ensure a sterile seal between the strikenpin holder 19 and the inner wall of the housing 1.

I The operation of the device is as follows. First the cover. 7 is removed and the pins 3 are thrust through the skin tissue against the lamina extema (see also FIG. 2). Then the cap 18 carrying the pin 17 is removed and the sleeve 15 is moved downwards with respect to the sheath 6 and the housing l,-the lugs 12 being pressed together by the conical bore 16, so that the faces 14 are disengaged from the seat 10. As a result, the element 11 with the collar 9 is thrust down by the action of the spring 8, a downward force being exerted on the striker-pin holder 19. This force causes the striker-pin holder 19 together with the striker pin 21 and the coupling member 22 to be driven to the open end 26 of the housing 1, until the lower surface 27 of the striker-pin holder 19 engages the shoulder 2 of the housing 1. During the last part of the distance travelled by the strikerpin holder 19 the pointed part 23 and the striker-pin tip 24 penetrate through the skin tissue 28 (FIG. 2) andthe lamina externa 29 (FIG. 2) into the bone marrow 30 (FIG. 2). v

FIG. 2 shows the device of FIG. 1 with the spring 8 relaxed and the striker-pin holder 19 in an extreme position. In this condition the lower surface 27 of the striker-pin holder 19 bears against the shoulder 2 of the housing 1. The pointed part 23 of the coupling member 22 and the tip 24 of the striker pin 21 extend through the skin tissue 28 and the lamina externa 29 into the bone marrow or diploe 30. The pins 3 set on the shoulder 2 extend through the skin tissue 28 up to the lamina externa 29. When the projecting part of the coupling member and the striker-pin up have been driven into the bone marrow by means of the device according to the invention, resulting in the situation shown in FIG. 2, the sleeve 15 together with the housing 1 is drawn upward. In this process the pins 3 are withdrawn from the skin tissue 28. The upper surface of the shoulder 2 exerts a force on the lower surface 27 of the striker-pin holder 19. When the force exerted exceeds the force of the friction between the coupling member 22 and the striker-pin holder 19, the striker-pin holder 19 slides along the outer surface 31 of the coupling member 22.

Because the striker-pin head 20 is enclosed in the striker-pin holder 19, the striker pin 21 is drawn upward together with the striker-pin holder 19. When the lower surface 32 of the housing 1 moves past the other surface 33 of the coupling member 22, the device is disconnected from the coupling member 22, resulting in the situation shown in FIG. 3.

In FIG. 3 the pointed part 23 of the coupling member 21 extends into the bone marrow 30. Its opening 34 is free and fluid can be administered to the bone marrow via an intermediate piece 35 having a bore 36. An end 37 of the intermediate piece 35 has a tapered outer surface, so that a fluid conduit 38 may clampingly be mounted on the end 37. The other end 39 of the intermediate piece 35 also is tapered and tits tightly in the end of the coupling member 22 remote from the opening 34. The intermediate piece 35 further is provided with a handle 40 which facilitates the connection of the intermediate piece 35 to the fluid conduit 38 at one end and to the coupling member 22 at the other end.

FIG. 4 shows a lower part of a device according to the invention which differs from that shown in FIG. 1 in that the shoulder 2 on the housing 1 is not provided with pins. Instead, the pins 3 aremounted on a cover 41 which is detachably secured to the housing 1 by a screwed connection 42. The cover may be formed with a central opening 43 which provides a passage for the striker pin and the coupling member, or it may be made, at least partly, of a material through which the striker-pin and the pointed part of the coupling member can pass. The'cover 41 is provided with a grip 44 to facilitate handling. The upper part of the device above a line BB is not shown but is identical to the part shown in FIG; 1 above a line AA.

FIG. shows the lower part of the device of FIG. 4 with the spring 8 relaxed and the striker-pin holder 19 in an extreme position. In this condition the lower surface 27 of the striker-pin holder 19 engages the shoulder 2 of the housing 1. The pointed part 23 of the coupling member 22 and the tip 24 of the striker pin 21 extend through the skin tissue 28 and the lamina extema 29 into the bone marrow 30. The cover 41 is pierced at the center, and a bevelled part 45 of the coupling member 22 is clamped in the rim 46 of the hole formed in the cover 41. The upper part of the device above a line C,'C is not shown but is identical to the part shown in FIG. 2 above a line DD.

When the pointed part 23 of the coupling member 22 and the striker-pin tip 24 have been driven into the bone marrow, resulting in the situation shown in FIG. 5, the housing 1 together with the sleeve is rotated, whilst the cover 41 is held'by means of the grip 44.

. Thus the housing 1 is screwed out of the cover 41. The

housing 1 in its upward movement carries along the striker-pin holder 19 and the striker pin 21 connected thereto; when the lower surface 46a of the shoulder 2 has moved past the upper surface 47 of the holder, the device isdisconnected from the coupling member 22, resulting in the situation shown in FIG. 6.

In FIG. 6 the pointed part 23 of the coupling member 22 extends through the skin 28 and the lamina extema 29 into the bone marrow 30. The bevelled part 45 of the coupling member 22 is clamped in the rim 46 of the hole pierced in the cover 41. Inthe same manner as shown in FIG. 3 a fluid conduit may be connected to the free end of the coupling member by means of an intermediate piece.

In FIG. 7 an elongate housing 1' is provided near its upper end with an opening 4 in which fit projections 5 on a spring sheath 6. At its other end the housing has a slit-shaped opening 48 which accommodates a wire spring 49. The wire spring 49 co-operates with a screwthreaded part 50 of a tablelike auxiliary member 51. The tablelike member 51 is formed with a passage 52 and its provided with three pins or legs 53 each of which have a cutting edge 54 at the free end. The tablelike member is enclosed in a sterile manner by a protective hood 55.

The spring sheath 6' accommodates a compressed spring 8' enclosed between a collar 9' and a seat 10'. The collar 9' is locked against displacement by means of a locking element 11' which is connected to the collar and at its upper end is provided with lugs 12'. The lugs have external bevelled parts 13' flat faces 14' of which bear on the rim of a seat 10'. The housing 1' and the spring sheath 6' are surrounded by a displaceable sleeve 15' which is provided with a conical bore 16 adapted to co-operate with the bevelled parts 13' of the lugs 12'. To prevent accidental actuation of the device a pin 17' is arranged in the space between the lugs 12' so that the lugs cannot be pressed together. The pin 17' is provided with a knob 18' by means of which it can be removed.

The housing I accommodates a displaceable strikerpin holder 72 which preferably is made of a synthetic material. The striker-pin holder 72 is a substantially cylindrical element which at its upper end is externally provided with projections 56 which fit in grooves 57 formed in the housing 1. The lower surface of the striker-pin holder 72 is provided with a coupling part which takes the form of pins 58 and co-operates with a coupling part in the form of recesses 59 in a coupling member 61. The coupling member 61 has an upper part 60 which preferably is made of a synthetic material and is provided with a central bore 62 in which a lower part 63 of the coupling member 61 is secured. The lower part 63 is substantially cylindrical and is made of a hard material, such as steel, and provided with a tapered sawtooth screwthread 64. Similarly to the upper part 60, the lower part 63 of the coupling member 61 is provided with a central bore 65 which registers with the central bore 62. A striker-pin 66 which is centrally secured in the lower part of the striker-pin holder 72 passes through the bores 62 and 65 so that its end provided with a cutting edge 67 projects slightly beyond the end (sawtooth screwthread 64) of the coupling member 61.

The striker-pin holder, the striker pin and the coupling member are held in place by frictional forces produced between the housing 1' and the striker-pin holder 72. the frictional froces are increased by providing the housing with an internal rib 68 which also ensures sterile closure.

The operation of the device shown in FIG. 7 is asfollows. The protective cover 55 is removed. The device is pressed against the skin of a patient at right angles thereto so that'the cutting edges 54 of the legs 53 of the auxiliary member 51 are thrust through the skin into contact with the lamina externa (outer compact bone layer) of a bone covered by the skinQThen the knob 18' carrying the pin 17 is removed and the sleeve 15 is moved downward with respect to the housing 1 and the sheath 6', the lugs 12 being pressed together by the bore 16, so that their faces 14 are disengaged from the seat 10'. As a result the element 11 provided with the collar 9' is thrust downward by the spring 8 and consequently exerts a force on the striker-pin holder 72. By the action of this force the striker-pin holder 72 with the striker pin 66 secured in it and the coupling member 61 connected to the striker pin move downward until the lower surfaces of the projections 56 strike the end walls of the grooves 57. During the downward movement of the striker-pin holder 72 the sawtooth screwthread 64 and the striker-pin tip 67 penetrate through the skin tissue into the bone. The depth of penetration of the sawtooth screwthread in the bone is about 4.5 mm. It should be noted that when the projections 56 strike the end walls of the grooves 57 the upper part 60 of the coupling member 61 does not yet fully engage the inner wall of the recess 52 of the auxiliary member 51, but still is removed therefrom by about 1.5 mm.

The outer sleeve 15 then is rotated. Because a strip 69 provided on the inner wall of the sleeve 15' passes through a recess in an annular thickened portion 70 of the spring sheath 6', rotation of the sleeve 15 entails rotation of the housing 1'. Because the projections 56 on the striker-pin holder 72 lie in grooves 57 in the housing 1, the striker-pin holder 72 and the coupling member 61 connected to it are also rotated. The result of the rotation is that the housing 1 provided with the wire spring 49 is unscrewed from the screwthreaded pling member has moved owing to the rotation of the sleeve 15' is about 1.5 mm. In this process the upper part 60 of the coupling member 61 is firmly clamped in the passage 52 in the auxiliary member 51. It should be noted that reverse rotation of the sleeve 15' produces a torque such that the wire spring 48 springs out of the groove 49. Thus the wire spring 48 provides protection against rotation in the wrong direction.

The sleeve 15' is then pulled upwards and removed together with the housing 1', the striker-pin holder 72 and the striker pin 66. The tablelike auxiliary member 51 and the coupling member 61 are left in the skin and the bone respectively of the patient. The central bore 62 in the upper part 60 of the coupling member 61 at its upper end forms a connection 71 for a fluid conduit. After a fluid conduit has been connected to the coupling member, a fluid may besupplied to, or withdrawn from, the bone marrow of a patient through the bore 62 and 65 in the coupling member 61.

As has been stated hereinbefore, FIG. 8 shows the part of the device of FIG. 7 which is left in the bone and the skin. In FIG. 8 reference numerals corresponding to those of FIG.7 denote like elements. In FIG. 8 the legs 53 of the auxiliary member 51 which are provided with cutting edges bear against the compact outer bone layer 136, the lamina externa, after having pierced the epidermis 132, the corium 133, the adipose tissue 134 and the periosteum 135. The couplingmember 61 ex tends in the passage 62 in the auxiliary member 51 and its upper part 60 is firmly clamped in this passage 52.

The lower part of the coupling member 61 has penetrated through the skin tissue, the adipose tissue and the outer compact bone layer into the bone marrow or substantia spongiosa 137, the sawtooth screwthread being inserted into the bone through a distance of 6 A fluid conduit may be connected to the connecting piece 71 of the coupling member 61. It should be noted that the legs 53 of the tablelike member 51 produce a high transverse stability of the coupling member 61 inserted into the bone marrow.

FIG. 9 shows part of a striker-pin holder 73. The part not shown is identical to the upper part of the strikerpin holder 72 shown in FIG. 7. At its lower end the striker-pin holder 73 is provided with a head 74 which carries a coupling piece 75. A striker pin 76 is firmly secured in the head 74. The coupling piece cooperates with a coupling part 77 of a coupling member 78. The coupling member 78 is formed with a central bore 79 the upper part 80 of which forms a connecting piece for a fluid conduit. The striker pin 76 passes through the central bore 79 and its blade-shaped end 81 projects slightly beyond the lower end 82 of the coupling member 78. The lower part of the coupling member 78 is provided with a tapered sawtooth screwthread 83 and further comprises a cylindrical part 84 situated above the sawtooth screwthread. A stylet 85 is so mounted on the cylindrical part as to be capable of rotating about it. The stylet 85 has winglike projections 86 which each have a cutting edge 87.

In the operation of the assembly shown in FIG. 9 the striker-pin end 81 and the sawtooth screwthread 83 penetrate through the skin tissue, the adipose tissue and the lamina externa of a patient into the bone marrow. This penetration is terminated when the cutting edges 87 of the wing-like projections 86 on the stylet 85 engage the lamina externa through the skin.

FIG. 10 shows a striker-pin holder88 which corresponds to the striker-pin holder 73 shown in FIG. 9. The striker-pin holder 88 also is provided with'a head 89 and a coupling part 90, a striker pin 91 being centrally secured in the head 89. The coupling piece cooperates with a coupling part 92 of a coupling member 93. The coupling member 93 is formed with a central bore 94 and its upper part 95 providesa connection for a fluid conduit. The striker-pin 91 passes through the central bore 94, a conical end 96 of the pin 91 projecting beyond the end 97 of the coupling member 93. The lower'part of the coupling member 93 is provided with a tapered sawtooth screwthread 98 and further comprises a cylindrical part 99 situated above the sawtooth screwthread. A trapezoidal stylet 101 provided with blades 100 is mounted on the cylindrical part 99 so as to be rotatable about it. The thickness of the stylet, i.e. its dimensions at right angles to the plane of the drawing, is greater than the thickness of the blades 100 secured to it, so that the lower surface of the stylet 101 forms an abutment 102. The blades, which extend slightly beyond the end 97 of the coupling member 93 and the striker-pin tip 96, are made of a very hard material, such as steel, and are capable of piercing not only skin tissue but also the compact bone layer.

In the operation of a device according to the invention which includes an assembly of a striker-pin holder, a striker pin and a coupling member, as shown in FIG. 10, the blades 100, the sawtooth screwthread 98 and the striker-pin end 96 penetrate through the skin tissue,

the adipose tissue and the lamina externa of a patient into the substantia spongiosa (bone marrow cavities). This movement is stopped by the abutment surface 102 of the stylet 101 striking the lamina externa.

FIG. 1 1 relates to an assembly of a striker-pin holder 103, a striker pin 104 and a coupling member 105, the striker-pin holder and the striker pin corresponding to those shown in FIG. 9. This means that the striker-pin holder is provided with a head 106 and a coupling piece 107 in which the strike pin 104, which is provided with a cutting edge 108, is centrally secured. The coupling member 105 is formed with a central bore 109 the upper part 110 of which acts as a connecting piece for a fluid conduit. The coupling member 105 at its upper end has a coupling part 111 capable of co-operating with the coupling piece 107 of the striker-pin holder 103. The coupling member is provided with a tapered sawtooth screwthread 112 at its lower end. The coupling member 105 further comprises a conical part 113 provided with an abutting face 114.

In the operation of the assembly shown in FIG. 1 1 the striker-pin end 108 and the sawtooth screwthread 112 penetrate through the skin tissue, the adipose tissue and the lamina externa of a patient into the bone marrow. The depth of penetration is restricted by the abutting face 114 bearing against the lamina externa.

FIG. 12 shows a striker-pin holder 115 which corresponds to the striker-pin holder 73 shown in FIG. 9. The striker-pin holder 115 is provided with a head 116, a coupling piece 1 17 and a striker-pin 1 18 which is centrally secured in the holder and the free end of which has a cutting edge 119. The coupling piece 117 cooperates with a coupling part 120 of a coupling member 121. The coupling member 121 is formed with a central bore 122 an upper part 123 of which acts as a connecting piece for a fluid conduit. The striker pin 118 extends through the central bore 122 in the coupling member 121 to a point beyond the end 124 of the coupling member 121. The coupling member 121 further comprises a tapered sawtooth screwthread 125 and is provided with a tablelike auxiliary member 126 which is connected to the coupling member 121 by means of a retaining ring 129. The inner surface 130 of the retaining ring is firmly clamped around the coupling member, while there is a certain amount of clearance between the outer wall 131 of the ring and the tablelike auxiliary member 126, permitting this member to rotate around the coupling member 121. The auxiliary member 126 has three legs 127 the free ends of which each have a cutting edge'l28.

When the assembly of a striker-pin holder, a striker pin, a coupling member and an auxiliary member shown in FIG. 12 is used in a device according to the invention and this device is pressed against the skin of a patient at right angles'thereto and then is actuated, the striker-pin end 119 and the sawtooth screwthread 125 penetrate through the skin and the lamina extema into the bone marrow. The cutting edges 128 of the legs 127 of the auxiliary member 126 will also pierce the skin. The movement of the striker-pin end 119 and the sawtooth screwthread into the bone marrow is terminated when the legs 127 of the auxiliary member 126 strike the lamina externa.

With respect to the embodiments of the assembly of a striker-pin holder, a striker pin, a coupling member and, as the case may be, an auxiliary member which are shown in FIGS. 9 to 12 the following should be noted for the sake of completeness.

When the striker pin and the sawtooth screwthread of the coupling member have been driven into the bone of a patient and, as the case may be, the auxiliary member has pierced the skin, the striker-pin holder containing the striker pin must be disconnected from the coupling member.

This is effected by twisting the striker-pin holder a quarter turn, causing the bayonet catch by which the coupling member is attached to the striker-pin holder to be unlocked. The striker-pin holder can be rotated by turning the sleeve 15 (see FIG. 7).

What is claimed is:

1. A device for inserting coupling means into human or animal bone marrow, comprising an elongated housing, a striker pin holder mounted within said housing for axial displacement, a substantially hollow coupling member having a pointed part and a central bore, said coupling member arranged within said housing adjacent said striker pin holder, a striker pin made of a hard material connected to said striker pin holder for movement therewith and extending through the central bore of said coupling member and beyond the end thereof, means at one end of said housing permitting passage therethrough of at least a part of said striker pin, a source of potential energy for exerting a force on said striker pin holder when released so as to cause movement thereof and drive said coupling member and said striker pin through the end of said housing and into the bone marrow when said device is placed on the surface of the skin of a patient and means for releasing said potential energy.

2. The device according to claiml further comprising a shoulder within said housing for acting as a stop for the striker pin holder so as to limit its axial movement and depth of penetration of said coupling member into said bone marrow.

3. The device according to claim 1 further comprising an auxiliary member connected to said elongated housing at the end thereof permitting passage of said striker pin for determining the depth of penetration of said coupling member into the bone marrow, said auxiliary member having atleast one pointed projection extending therefrom for penetrating the skin of the patient.

4. The device according to claim 3 wherein said auxiliary member comprises an internally thickened portion of said elongated housing being integral therewith and located at the end thereof permitting passage of said striker pin.

5. The device according to claim 3 wherein said auxiliary member comprises a cover detachably secured to said housing having a central opening through which said striker pin and pointed part of said coupling member can pass.

6. The device according to claim 3 wherein said auxiliary member comprises a cover detachably secured to said housing the centerthereof being made of a material through which said striker pin and pointed part of said coupling member can pass.

7. The device according to claim 3 wherein said aux,-

iliary member comprises a tablelike element having legs with cutting edges, said element being detachably connected to said elongated housing at the erid thereof permitting passage of said striker pin, means for detachably connecting the element to said housing comv prising cooperating coupling parts on said element and said housing, and a recess in said element in the surface thereof facing away from said legs forming a passage for the striker pin and the pointed part of said coupling member.

8. The device according to claim 7 further comprising a tapered sawtooth screwthread at the end of said pointed part of said coupling member, the direction of said screwthread being opposite to the direction of said coupling part of said tablelike element.

9. The device according to claim 1 further comprising an auxiliary member connected to said coupling member for determining the depth of insertion thereof into the bone marrow, said auxiliary member having a plurality of pointed projections extending therefrom for penetrating the skin of the patient.

10. The device according to claim 9 wherein said auxiliary member comprises a stylet connected to said coupling member having at least one wing-like projection provided with a cutting edge.

11. The device according to claim 1 wherein said striker pin holder is substantially cylindrical, said striker pin being centrally secured therein at the lower end thereof, coupling means arranged at the lower surface of said striker pin holder for cooperative engagement with cooperating means on the upper surface of said coupling member to said striker pin holder.

12. The device according to claim 1 further comprising a tapered sawtooth screwhead at the end of said pointed part of said coupling member.

13. The device according to claim 1 further comprising at least one projection on the outer surface of said striker pin holder, and a groove on the inner surface of said housing receiving said projection, said groove extending nearly to the open end of said housing. 

1. A device for inserting coupling means into human or animal bone marrow, comprising an elongated housing, a striker pin holder mounted within said housing for axial displacement, a substantially hollow coupling member having a pointed part and a central bore, said coupling member arranged within said housing adjacent said striker pin holder, a striker pin made of a hard material connected to said striker pin holder for movement therewith and extending through the central bore of said coupling member and beyond the end thereof, means at one end of said housing permitting passage therethrough of at least a part of said striker pin, a source of potential energy for exerting a force on said striker pin holder when released so as to cause movement thereof and drive said coupling member and said striker pin through the end of said housing and into the bone marrow when said device is placed on the surface of the skin of a patient and means for releasing said potential energy.
 2. The device according to claim 1 further comprising a shoulder within said housing for acting as a stop for the striker pin holder so as to limit its axial movement and depth of penetration of said coupling member into said bone marrow.
 3. The device according to claim 1 further comprising an auxiliary member connected to said elongated housing at the end thereof permitting passage of said striker pin for determining the depth of penetration of said coupling member into the bone marrow, said auxiliary member having at least one pointed projection extending therefrom for penetrating the skin of the patient.
 4. The device according to claim 3 wherein said auxiliary member comprises an internally thickened portion of said elongated housing being integral therewith and located at the end thereof permitting passage of said striker pin.
 5. The device according to claim 3 wherein said auxiliary member comprises a cover detachably secured to said housing having a central opening through which said striker pin and pointed part of said coupling member can pass.
 6. The device according to claim 3 wherein said auxiliary member comprises a cover detachably secured to said housing the center thereof being made of a material through which said striker pin and pointed part of said coupling member can pass.
 7. The device according to claim 3 wherein said auxiliary member comprises a tablelike element having legs with cutting edges, said element being detachably connected to said elongated housing at the end thereof permitting passage of said striker pin, means for detachably connecting the element to said housing comprising cooperating coupling parts on said element and said housing, and a recess in said element in the surface thereof facing away from said legs forming a passage for the striker pin and the pointed part of said coupling member.
 8. The device according to claim 7 further comprising a tapered sawtooth screwthread at the end of said pointed part of said coupling member, the direction of said screwthread being opposite to the direction of said coupling part of said tablelike element.
 9. The device according to claim 1 further comprising an auxiliary member connected to said coupling member for determining the depth of insertion thereof into the bone marrow, said auxiliary member having a plurality of pointed projections extending therefrom for penetrating the skin of the patient.
 10. The device according to claim 9 wherein said auxiliary member comprises a stylet connected to said coupling member having at least one wing-like projection provided with a cutting edge.
 11. The device according tO claim 1 wherein said striker pin holder is substantially cylindrical, said striker pin being centrally secured therein at the lower end thereof, coupling means arranged at the lower surface of said striker pin holder for cooperative engagement with cooperating means on the upper surface of said coupling member to said striker pin holder.
 12. The device according to claim 1 further comprising a tapered sawtooth screwhead at the end of said pointed part of said coupling member.
 13. The device according to claim 1 further comprising at least one projection on the outer surface of said striker pin holder, and a groove on the inner surface of said housing receiving said projection, said groove extending nearly to the open end of said housing. 